Mueller would need go-ahead to expand Russia probe: Justice official

Special counsel Robert Mueller appears to be stepping up his probe of the Russia election meddling scandal

US special prosecutor Robert Mueller would need clearance from above to expand his Russia probe into areas outside the original scope of the investigation, a top Justice Department official said Sunday.

"We don't engage in fishing expeditions," said Rod Rosenstein, the deputy attorney general who appointed Mueller, a former FBI director, to investigate links between US President Donald Trump's campaign and a covert Russian effort to tip the 2016 US elections in his favor.

Trump, a billionaire real estate developer, has said he considered scrutiny of his family's finances a "red line" that the federal probe should not cross.

If Mueller "finds evidence of a crime that's within the scope of what the director and I have agreed is the appropriate scope of the investigation, then he can," Rosenstein said in an interview with Fox News Sunday.

Rosenstein, who appointed Mueller special counsel, empowered him to investigate "any matters that arose or might arise directly from the investigation."

Trump has lashed out at Attorney General Jeff Sessions for recusing himself from the Russia probe, blaming him for Mueller's appointment as special counsel while railing at press leaks.

The displays of presidential anger have come as Mueller's work appears to be picking up steam, having put in place an all-star team of veteran former prosecutors.

A grand jury is reported to have been empaneled in Washington to look at evidence, and the White House has been asked for documents related to former national security adviser Michael Flynn, who was fired shortly after taking office for his undisclosed Russia contacts.

Trump seemed somewhat mollified this week after Sessions announced that the Justice Department has tripled the number of leak investigations, and that a special unit has been set up to handle those cases.

"After many years of LEAKS going on in Washington, it is great to see the A.G. taking action! For National Security, the tougher the better!" the president tweeted on Saturday.

Rosenstein said policies on subpoenaing journalists for their sources were under review.

But he insisted "we are after the leakers, not the journalist.

"We are after the people committing crime, so we will devote the resources we need to identify who is responsible for those leaks and who's violated the law, and hold them accountable."